The present invention relates to a microcomputer and, more particularly, to an improvement of a microcomputer which is required to read out internal conditions such as contents of general purpose registers in the course of executing a program.
A microcomputer is widely used in various electronic apparatus to control operations thereof. It is needless to say that the microcomputer executes a string of instructions for a program to perform desired operations. It is therefore required to check whether the program is properly written. Checking the program is carried out by intermittently reading out internal conditions such as contents of general purpose registers during the execution of the program.
For this purpose, an In-Circuit-Emulator (ICE) system is provided as well known in the art. This system includes a microcomputer for emulation (i.e., "emulation microcomputer") executing the program in place of a microcomputer which is actually employed in an electronic apparatus and further having functions of outputting internal conditions under the control of an emulation program. The ICE system is thus provided for every kind or family of microcomputer. In other words, the ICE system is required to be prepared for every kind of microcomputer.